Author Topic: My Jazz SR arrived yesterday  (Read 1351 times)

olduser1

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Re: My Jazz SR arrived yesterday
« Reply #15 on: July 09, 2020, 06:05:05 PM »
Maybe as well to do the old fill to fill over a month or so of mixed driving then check mpg.

csp

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Re: My Jazz SR arrived yesterday
« Reply #16 on: July 10, 2020, 10:58:28 AM »
I suspect that the engine will run in cold weather to provide heating, the manual implies that the system may take longer to initialise in very cold weather  (see attachment), I also suspect that in cold weather the range in EV mode would be reduced so the engine would run more.


« Last Edit: July 10, 2020, 11:00:52 AM by csp »

John Ratsey

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Re: My Jazz SR arrived yesterday
« Reply #17 on: July 10, 2020, 11:50:39 AM »
My dealer sent me a link to this introductory video: Honda UK have prepared it because social distancing requirements prevent the salesman from sitting in the vehicle with the customer and explaining the controls.

At about 2m 55s there's a comment explaining that whether or not the engine starts when the vehicle is first powered up depends on both the state of battery charge (I presume he means the HV battery) and the temperature both inside and outside the vehicle. This, I deduce, means that the engine is needed for both heating and cooling. The handbook explains that enabling Econ mode allows greater temperature fluctuations (ie the vehicle will tolerate a bigger temperature difference between target and actual temperature before the engine gets started).

I'm a little surprised that, given all the technology packed under the bonnet, Honda didn't include an inverter controlled electrical aircon / heat pump. They must have one in the parts store for the Honda e but perhaps they were worried by the prospect of people sitting in the vehicle for sustained periods, going nowhere but draining the battery.

Muldoon

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Re: My Jazz SR arrived yesterday
« Reply #18 on: July 10, 2020, 12:10:13 PM »
I suspect that the engine will run in cold weather to provide heating, the manual implies that the system may take longer to initialise in very cold weather  (see attachment), I also suspect that in cold weather the range in EV mode would be reduced so the engine would run more.

Thanks for this, an interesting detail. It does say you can't drive off until conditions improve, I wonder for how long? If it is minus 8 and thick ice on the car it may prevent you driving off until certain levels and readings comply. Suppose you can defrost and scrape off the ice whilst the car initialises? I don't think the new Jazz has a heated windscreen.

Muldoon

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Re: My Jazz SR arrived yesterday
« Reply #19 on: July 10, 2020, 12:12:05 PM »
My dealer sent me a link to this introductory video: Honda UK have prepared it because social distancing requirements prevent the salesman from sitting in the vehicle with the customer and explaining the controls.

At about 2m 55s there's a comment explaining that whether or not the engine starts when the vehicle is first powered up depends on both the state of battery charge (I presume he means the HV battery) and the temperature both inside and outside the vehicle. This, I deduce, means that the engine is needed for both heating and cooling. The handbook explains that enabling Econ mode allows greater temperature fluctuations (ie the vehicle will tolerate a bigger temperature difference between target and actual temperature before the engine gets started).

I'm a little surprised that, given all the technology packed under the bonnet, Honda didn't include an inverter controlled electrical aircon / heat pump. They must have one in the parts store for the Honda e but perhaps they were worried by the prospect of people sitting in the vehicle for sustained periods, going nowhere but draining the battery.

Thanks for this John, very interesting. There is a lot going on under the bonnet with competing systems and sensors, it does suggest a delay to driving if it is very cold.

Jocko

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Re: My Jazz SR arrived yesterday
« Reply #20 on: July 10, 2020, 02:10:33 PM »
I'm a little surprised that, given all the technology packed under the bonnet, Honda didn't include an inverter controlled electrical aircon / heat pump. They must have one in the parts store for the Honda e but perhaps they were worried by the prospect of people sitting in the vehicle for sustained periods, going nowhere but draining the battery.
The difference in battery capacity is HUGE between the Jazz and the Honda-e (even though the Honda-e is small compared with the Kona, Niro and Tesla). It is not surprising that the engine has to run to provide heating and cooling. If you are happy to suffer, you can use the Econ mode, just as in an EV you can wrap up warm and do without cabin heating (seat heaters appear to be a more energy-efficient means of keeping warm in an EV).
The bit about "the manual implies that the system may take longer to initialise in very cold weather" is worrying, if the car won't start in extremely low temperatures.

John Ratsey

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Re: My Jazz SR arrived yesterday
« Reply #21 on: July 10, 2020, 04:11:01 PM »
The bit about "the manual implies that the system may take longer to initialise in very cold weather" is worrying, if the car won't start in extremely low temperatures.
How cold is "very cold"? I guess somewhere like -20C as Honda are selling the same vehicle all over Europe and many countries have colder winters than we get. Even if "very cold" is as high as -10C I'm very unlikely to be venturing outside but maybe it's a more common occurrence for you folk who live near the Arctic circle ;D .

A heat pump typically produces 4 x more heat than it uses as energy so a 0.5kW heat pump could provide 2kW of heating. A few minutes fill-in warmth from battery power would avoid the cold engine idling when waiting at traffic lights or junctions and cold engines are bad for the mpg. If the engine only has to run when it's actually delivering power then it will warm up faster (perhaps Honda has configured the vehicle so that the engine does a bit of work topping up the battery). We'll find out next winter.

Jocko

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Re: My Jazz SR arrived yesterday
« Reply #22 on: July 10, 2020, 07:07:21 PM »
A heat pump typically produces 4 x more heat than it uses as energy so a 0.5kW heat pump could provide 2kW of heating.
These figures are for a "Ground Source Heat Pump" so unless you bury the car in the ground, I cannot see how you can get that amount of energy. EV heat pumps use the heat from the battery to heat the cabin. I very much doubt a Hybrid battery would develop enough heat to make a heat pump viable.
However, I am sure Honda has made cabin heating effective. After all, Japan has bitterly cold winters (Winter Olympics).

culzean

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Re: My Jazz SR arrived yesterday
« Reply #23 on: July 10, 2020, 08:22:47 PM »
An air source heat pump or reverse cycle air conditioning has about a 2:1 gain, but does not perform well at lower temperatures ( below about 5deg C )
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

jazzaro

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Re: My Jazz SR arrived yesterday
« Reply #24 on: July 11, 2020, 09:39:46 PM »
I'm a little surprised that, given all the technology packed under the bonnet, Honda didn't include an inverter controlled electrical aircon / heat pump. They must have one in the parts store for the Honda e but perhaps they were worried by the prospect of people sitting in the vehicle for sustained periods, going nowhere but draining the battery.
Honda-e is a full electric vehicle, so there are two ways to heat the cabin, one is a PTC heater, other is a heat pump; since the PTC resistor is less efficient, they use a heat pump.
Jazz and CR-V are hybrid vehicles, with an about 1,3kw lithium ion battery used to have the petrol engine run in best efficiency range. So they have lots of heat coming from the petrol engine, heat that would be wasted when not used for the cabin.
Why should Honda use a heat pump in its hybrids to heat the cabin, using the petrol engine to generate electricity (and wasting heat that could be easily used)  to move the heat pump in a less efficient process?
« Last Edit: July 12, 2020, 10:41:59 AM by jazzaro »

John Ratsey

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Re: My Jazz SR arrived yesterday
« Reply #25 on: July 12, 2020, 01:04:52 PM »
Jazz and CR-V are hybrid vehicles, with an about 1,3kw lithium ion battery used to have the petrol engine run in best efficiency range. So they have lots of heat coming from the petrol engine, heat that would be wasted when not used for the cabin.
Why should Honda use a heat pump in its hybrids to heat the cabin, using the petrol engine to generate electricity (and wasting heat that could be easily used)  to move the heat pump in a less efficient process?
Using engine heat is fine once the engine has warmed up but running the engine on a cold day just to provide heating is going to make a big hit on the fuel economy, especially during the first few miles when the engine itself is cold and needs extra fuel to run properly. I wait to see what happens in reality. The CR-V has been provided with thermostatically-controlled lourvres on the front of the engine compartment to reduce the inflow of very cold air and help the engine warm up more quickly but this feature isn't provided on the Mk 4 Jazz.

Pine

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Re: My Jazz SR arrived yesterday
« Reply #26 on: July 12, 2020, 06:17:56 PM »
I suspect that the engine will run in cold weather to provide heating, the manual implies that the system may take longer to initialise in very cold weather  (see attachment), I also suspect that in cold weather the range in EV mode would be reduced so the engine would run more.
I had a look at the online manual and the cold weather temperatures it quotes are -30c and -40c.  So it's not going to be a problem in the UK.

jazzaro

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Re: My Jazz SR arrived yesterday
« Reply #27 on: July 12, 2020, 07:01:49 PM »
The main purpose of mobile louvres is to have a better aerodynamic, Jazz does not have this and other useful features  to keep it cheap. A device present on some Honda hybrids is the heat exchanger used to exctract heat from exaust gas, placed after the kat converter; Accord and CR-V hybrid (both with a 2.0l engine) have it, while other hybrids with the 1.5l does not fit it, Insight and probably Jazz. Same reason, Jazz would become too expensive with all this feauters.
About the heat pump... Having it would mean to have a complicated compressor, an inverter and a bigger battery if you want the compressor to run with the petrol engine off and this would hardly prevent the petrol engine to run, because the heat pump need energy; they could use a  bigger battery but this bigger battery should be recharged. Is this a good idea for a cheap car, considering that this would be useful only in the first 3-4 minutes of usage?
« Last Edit: July 12, 2020, 07:11:58 PM by jazzaro »

jazzaro

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Re: My Jazz SR arrived yesterday
« Reply #28 on: July 12, 2020, 07:07:44 PM »
I suspect that the engine will run in cold weather to provide heating, the manual implies that the system may take longer to initialise in very cold weather  (see attachment),
Surely it will do it, the system is not so different from Toyotas...
Quote
I also suspect that in cold weather the range in EV mode would be reduced so the engine would run more.
Also this will happen, even if this is not an EV vehicle so you won't have to force it in EV mode.

TnTkr

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Re: My Jazz SR arrived yesterday
« Reply #29 on: Today at 06:27:27 AM »
Using engine heat is fine once the engine has warmed up but running the engine on a cold day just to provide heating is going to make a big hit on the fuel economy, especially during the first few miles when the engine itself is cold and needs extra fuel to run properly. I wait to see what happens in reality. The CR-V has been provided with thermostatically-controlled lourvres on the front of the engine compartment to reduce the inflow of very cold air and help the engine warm up more quickly but this feature isn't provided on the Mk 4 Jazz.
With every combustion engine it is advisable and beneficial for fuel economy as well as to reduce engine wear to use mains electric engine pre-heater (block heater or hose type) when temperature drops below freezing point. For sure some type of pre-heater is possible to install to GR Jazz engine.

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